Study of ignition and combustion of coal and coal chars; using a special shock tube system

The feasibility of using a special shock-tube system as a method for studying the ignition and burning of coal and coal chars was investigated. The system operating limits for the characterization of the ignition and combustion process were determined, and a preliminary evaluation of data was made. Sample particles of 25 ym were used in the study. Two samples of coal char were tested to determine their ignition characteristics. Significant data were obtained concerning the ignition and burning of the coal and both of the chars tested. Except for a significant difference in the intensity of visible radiation noted while burning, the ignition and burning properties of the coal and its chars were quite similar. The effects of gas temperature, total pressure, and oxygen content were determined. The data obtained were evaluated in terms of the thermal theory of ignition in an attempt to model the ignition process. It was found that the simple thermal ignition theory did not accurately describe the data obtained from the special shock tube system.